Delayed psilocybin treatment after repeated mild traumatic brain injury recovers chronic behavioural deficits, reduces microglial density, and enhances hippocampal neurogenesis in rats
Research Square February 23, 2026 Sandy R Shultz, Josh Allen, Grace O'Regan et al.
Repeated mild traumatic brain injury in rats produced lasting deficits in mood, social behavior, and pain sensitivity. Delayed treatment with psilocybin (1 mg/kg) reversed several of these effects, including antidepressant-like effects, increased social behavior, and raised pain thresholds. Psilocybin also reduced injury-related increases in microglial density and increased the number and complexity of newborn neurons in the dentate gyrus, suggesting enhanced neuroplasticity. The findings indicate psilocybin may be a promising intervention for persistent symptoms after repeated mild traumatic brain injury.